#include <stdio.h>


int main() 
{
    int n,time=0;
    scanf("%d",&n);

    while(n>=12)
    {
        n = n-12;
        time = time + 4;
    }

    if(n<12)
    {
        time = time + 2;
    }
    
    printf("%d",time);

    return 0;
}